1. Field of the Invention
The present invention relates to a height adjusting device used with an automotive seat, which is adapted for adjusting the seating height of the seat, and in particular to a locking device for such height adjusting device.
2. Description of the Prior Art
Among the known locking mechanisms for seat height adjusting device, there are disclosed the ones, for example, from the Japanese Laid-Open Publication No. 60-206739 and U.S. Pat. No. 4,616,876. According to the former Japanese prior art, a stopper and lock gear arrangment is described as being operable by a lever such that the stopper is engaged with or disengaged from the lock gear by virtue of the lever being rotated, and the lever is normally biased to a predetermined position by a spring means in a sense causing the lever to return to that position after the rotation thereof for seat height adjustment. As regards the latter U.S. prior art, the locking and unlocking of seat height adjusting device is effected by a manually extending and retracting operations of a telescope lever, according to which a lock gear is disengaged from a fixed gear by drawing out the lever through the associated movement of a wire assembly, and after vertical rotation of the lever for the height adjustment, the drawing back of the lever causes the engagement of the lock gear with the fixed gear for locking the seat height adjusting device.
However, the above-mentioned prior arts are found to have their inherent drawbacks in that, in the Japanese one, there is a great possibility of the stopper being released from its engagement with the lock gear when a load is applied to the spring means during the rolling or jolting of an automobile and in the U.S. one, before adjusting the seat height, an occupant on the seat has to draw out the lever for disengaging the lock gear from the fixed gear and rotate the lever, thus resulting in a troublesome operation and waste of time.